1. Field of the Invention
The invention relates to a medicinal or dental hand instrument which includes a handpiece and a handle arranged on the hand piece, and which incorporates a coupling element for coupling the hand instrument to a supply line for at least one transport fluid.
2. Discussion of the Prior Art
A hand instrument of this type has been described in each of publications U.S. Pat. No. 2,814,877, IT 1180538 and U.S. Pat. No. 4,648,840.
A common feature of these known hand instruments is a rod-shaped hand piece which in its front end zone has an outlet nozzle for a therapeutic agent and at its rear end has a coupling terminal for the detachable coupling of the hand piece to a flexible supply line. From the coupling terminal one or more feed lines for the therapeutic agent extend through the hand piece to the outlet terminal.
The hand piece described in U.S. Pat. No. 2,814,877 comprises a storage container for the therapeutic agent at its rear end. The coupling terminal for the supply line is arranged at the rear end of the storage container, the feed line extending coaxially through the container. The hand piece is a body permanently assembled from a plurality of longitudinal parts. In the front end zone of the hand piece a valve is arranged in the feed line, said, valve being selectively manually opened or closed by a transversely projecting actuating element. The outlet opening is situated at the front end of a hollow needle which projects from the hand piece and whose free end extends obliquely forwards relative to the longitudinal central axis of the hand instrument.
A known hand instrument somewhat comparable with the previously described known hand instrument has been described in IT 1180538. In its rear end zone this hand instrument likewise comprises a storage chamber for the therapeutic agent, a first and second centrifugal chamber for the therapeutic agent being arranged in the front half of the hand piece.
In contrast to the previously described modes of construction, a dental hand instrument described in U.S. Pat. No. 4,648,840 comprises a laterally projecting storage container which is arranged in the rear end zone of the hand instrument.
A hand instrument of the present type has to fulfil i.a. two requirements. On the one hand, it is to be easy to handle in order to be able to be moved and guided purposively and safely during use with the least possible exertion. On the other hand, a simple construction which can be manufactured cost-effectively is advisable, which in particular is of essential significance in view of the relatively small structural space available. Here it should be kept in mind that the feed line between the coupling component associated with the supply line and the coupling component associated with the hand instrument and the ongoing feed line are complex and the manufacture of these feed line sections requires a relatively large outlay in terms of production and time, with the result that the manufacturing costs are also high.
The object of the invention is, in the case of a hand instrument of the type described adapted to simplify and improve upon the coupling means for coupling to the supply line.
In this embodiment the associated coupling component and one or more coaxially or paraxially disposed, sealed pipe socket couplings are formed on a separate insert piece which can be premanufactured and assembled simply and cost-effectively. The hand piece can have a substantially simpler construction in the region of the coupling terminal. The reason for this is that the production of the feed line formed on the one hand in the separate insert piece and on the other hand in the hand instrument with the insert piece removed, thereby providing improved accessibility, is simpler and easier. This is also contributed towards by the design of the one or more pipe socket coupling(s) present between the insert piece and the hand piece, which can be produced and sealed in a simple manner and facilitate a small construction.
This embodiment according to the invention also allows the insert piece to be used as adapter for adapting the hand instrument to different coupling components associated with the supply line, when a plurality of insert pieces matching coupling components produced by different manufacturers are provided. This allows a simple adaptation of the hand instrument to different manufacturers of supply lines or devices, which adaptation can be carried out with ease of handling and both rapidly and cost-effectively.
It is a further object of the invention to design a medicinal or dental hand instrument of the type described herein so as to facilitate simpler and improved handling.
In this embodiment according to the invention, the handle, with an optionally provided hollow needle, can be rotated simply and with ease of handling independently of the rearwardly arranged shaft, and the outlet opening can be brought into selective positions. This substantially simplifies a purposive treatment of the teeth of a jaw, or of the lower- and upper jaw.
It is also advantageous to arrange the coupling terminal laterally on the hand instrument. In this way the effective lever load exerted upon the hand instrument by the flexible supply line during the handling of the hand instrument can be substantially reduced. This is due to the fact that on the one hand, on account of the lateral coupling terminal, the effective load gravity point of the flexible supply line is displaced towards the hand instrument. On the other hand, the effective distance between the coupling terminal and the handle can be substantially reduced, so that the stabilisation moment to be applied by the operator""s hand during the handling of the hand instrument is also substantially reduced in this way. The advantageous outcome is that the operator can move and guide the hand instrument more simply, more easily and with less attentiveness. Consequently the operator can concentrate more upon the actual treatment with the result that an improvement in the quality of the treatment can also be achieved.
The coatings or discolourations present on body parts, in particular teeth, can be of different types and consistencies.
Therefore it is a further object of the invention to design a hand instrument of the type described in such manner that the respective body part can be purposively treated and/or the hand instrument can be adapted to the particular treatment.
In accordance with the invention, a plurality of therapeutic agents having different removing capacities can selectively be used. In this way different coatings and/or discolourations can be treated with a therapeutic agent having a greater or lesser removing capacity, on the one hand with the correct power level and on the other hand gently and thus purposively, e.g. using a therapeutic agency having a fine, medium or coarse removing capacity. Here it should be kept in mind that, in particular in the case of treatment with a coarse-acting therapeutic agent, depending upon the aggressiveness of the therapeutic agent a slight erosion of tooth substance is likely. This can be avoided or reduced to a minimum by means of the invention.
Further developments of these features of the invention facilitate a simple and easily handled adaptation of the therapeutic instrument to different therapeutic agents, and at the same time the selection of the implementation of the adaptation is simplified and facilitated.
It is a further object of the invention to protect the interior of the hand piece from contamination.
In one embodiment according to the invention, in functional operation the interior of the hand piece is subjected to excess pressure which prevents impurities and pathogenic organisms from penetrating through crevices and gaps.
It is a further object of the invention to design a hand instrument of the type described herein in such manner that contamination of the coupling is prevented.
In this embodiment an automatic closure of the feed line in the direction of the coupling takes place. In this way, in the event of an obstruction of the hand instrument, pressure relief noises and contamination upon the opening of the coupling are avoided.
It is a further object of the invention to design a hand instrument of the type described herein in such a manner that, independently of the position of the hand instrument, a substantially uniform mixture of the carrier fluid and the abrasive therapeutic agent is obtained.
This object is fulfilled by the present invention. In this embodiment the inlet opening for the transport fluid and the inner outlet opening for the mixture are situated in the central region of the accommodating chamber of the storage container. In this way these openings are situated in a region of the accommodating chamber in which, independently of the position of the hand instrument, a substantially uniform mixture quantity and concentration can discharge through the inner outlet opening. This is of considerable advantage as during the treatment the hand instrument can be held in different positions in particular in the mouth cavity of a patient, and nevertheless a substantially constant mixture is outlet from the outlet opening of the handle.
The invention further relates to an advantageous pressure relief device for the storage container which facilitates a clean opening of the storage container even when the latter is under pressure, for example in the case of an obstruction in the region of the hand instrument.